[Lldb-commits] [lldb] 93b2551 - [LLDB] Fix how ValueObjectVariable handles DW_AT_const_value when the DWARFExpression holds the data that represents a constant value
via lldb-commits
lldb-commits at lists.llvm.org
Mon Aug 24 15:17:37 PDT 2020
Author: shafik
Date: 2020-08-24T15:17:27-07:00
New Revision: 93b255142bb7025f62cf83dd5b7d3b04aab5445b
URL: https://github.com/llvm/llvm-project/commit/93b255142bb7025f62cf83dd5b7d3b04aab5445b
DIFF: https://github.com/llvm/llvm-project/commit/93b255142bb7025f62cf83dd5b7d3b04aab5445b.diff
LOG: [LLDB] Fix how ValueObjectVariable handles DW_AT_const_value when the DWARFExpression holds the data that represents a constant value
In some cases when we have a DW_AT_const_value and the data can be found in the
DWARFExpression then ValueObjectVariable does not handle it properly and we end
up with an extracting data from value failed error.
The test is a very stripped down assembly file since reproducing this relies on the results of compiling with -O1 which may not be stable over time.
Differential Revision: https://reviews.llvm.org/D86311
Added:
lldb/test/Shell/SymbolFile/DWARF/DW_AT_const_value.s
Modified:
lldb/source/Core/ValueObjectVariable.cpp
Removed:
################################################################################
diff --git a/lldb/source/Core/ValueObjectVariable.cpp b/lldb/source/Core/ValueObjectVariable.cpp
index ab67e3038cf0..43e888a68725 100644
--- a/lldb/source/Core/ValueObjectVariable.cpp
+++ b/lldb/source/Core/ValueObjectVariable.cpp
@@ -132,8 +132,11 @@ bool ValueObjectVariable::UpdateValue() {
if (variable->GetLocationIsConstantValueData()) {
// expr doesn't contain DWARF bytes, it contains the constant variable
// value bytes themselves...
- if (expr.GetExpressionData(m_data))
+ if (expr.GetExpressionData(m_data)) {
+ if (m_data.GetDataStart() && m_data.GetByteSize())
+ m_value.SetBytes(m_data.GetDataStart(), m_data.GetByteSize());
m_value.SetContext(Value::eContextTypeVariable, variable);
+ }
else
m_error.SetErrorString("empty constant data");
// constant bytes can't be edited - sorry
diff --git a/lldb/test/Shell/SymbolFile/DWARF/DW_AT_const_value.s b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_const_value.s
new file mode 100644
index 000000000000..09c369ff083a
--- /dev/null
+++ b/lldb/test/Shell/SymbolFile/DWARF/DW_AT_const_value.s
@@ -0,0 +1,409 @@
+# REQUIRES: x86
+
+# RUN: llvm-mc -filetype=obj -o %t -triple x86_64-apple-macosx10.15.0 %s
+# RUN: %lldb %t -o "target variable constant" -b | FileCheck %s
+
+# CHECK: (lldb) target variable constant
+# CHECK: (U) constant = {
+# CHECK: raw = 1688469761
+# CHECK: = (a = 1, b = 1, c = 36, d = 2, e = 36, f = 1)
+# CHECK: }
+
+# Test we are able to display a variable whose value is given by DW_AT_const_value.
+# Compiling at -O1 allows us to capture this case. Below is the code used
+# to generate the assembly:
+#
+# typedef union
+# {
+# unsigned raw;
+# struct
+# {
+# unsigned a : 8;
+# unsigned b : 8;
+# unsigned c : 6;
+# unsigned d : 2;
+# unsigned e : 6;
+# unsigned f : 2;
+# } ;
+# } U;
+#
+# static U __attribute__((used)) _type_anchor;
+# static const int constant = 0x64A40101;
+#
+# int g() { return constant; }
+#
+# int main() {
+# U u;
+# u.raw = 0x64A40101;
+# }
+#
+# Compiled as follows:
+#
+# clang -gdwarf-4 -O1 dw_at_const_value_bug.c -S -o dw_at_const_value_bug.s
+#
+# I was not able to obtain a global of type U with DW_AT_const_value but was able
+# to using int. This required modifying the DW_AT_type of constant to be type
+# U. After that stripping as much of the assembly as possible to give us a
+# smaller reproducer.
+
+
+.zerofill __DATA,__bss,__type_anchor,4,2 ## @_type_anchor
+ .no_dead_strip __type_anchor
+ .section __DWARF,__debug_str,regular,debug
+Linfo_string:
+ .zero 90
+ .asciz "constant" ## string offset=90
+ .asciz "int" ## string offset=99
+ .asciz "_type_anchor" ## string offset=103
+ .asciz "U" ## string offset=116
+ .asciz "raw" ## string offset=118
+ .asciz "unsigned int" ## string offset=122
+ .asciz "a" ## string offset=135
+ .asciz "b" ## string offset=137
+ .asciz "c" ## string offset=139
+ .asciz "d" ## string offset=141
+ .asciz "e" ## string offset=143
+ .asciz "f" ## string offset=145
+ .asciz "g" ## string offset=147
+ .asciz "main" ## string offset=149
+ .asciz "u" ## string offset=154
+ .section __DWARF,__debug_abbrev,regular,debug
+Lsection_abbrev:
+ .byte 1 ## Abbreviation Code
+ .byte 17 ## DW_TAG_compile_unit
+ .byte 1 ## DW_CHILDREN_yes
+ .byte 37 ## DW_AT_producer
+ .byte 14 ## DW_FORM_strp
+ .byte 19 ## DW_AT_language
+ .byte 5 ## DW_FORM_data2
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 66 ## DW_AT_stmt_list
+ .byte 23 ## DW_FORM_sec_offset
+ .byte 27 ## DW_AT_comp_dir
+ .byte 14 ## DW_FORM_strp
+ .ascii "\264B" ## DW_AT_GNU_pubnames
+ .byte 25 ## DW_FORM_flag_present
+ .ascii "\341\177" ## DW_AT_APPLE_optimized
+ .byte 25 ## DW_FORM_flag_present
+ .byte 17 ## DW_AT_low_pc
+ .byte 1 ## DW_FORM_addr
+ .byte 18 ## DW_AT_high_pc
+ .byte 6 ## DW_FORM_data4
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 2 ## Abbreviation Code
+ .byte 52 ## DW_TAG_variable
+ .byte 0 ## DW_CHILDREN_no
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 28 ## DW_AT_const_value
+ .byte 15 ## DW_FORM_udata
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 3 ## Abbreviation Code
+ .byte 38 ## DW_TAG_const_type
+ .byte 0 ## DW_CHILDREN_no
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 4 ## Abbreviation Code
+ .byte 36 ## DW_TAG_base_type
+ .byte 0 ## DW_CHILDREN_no
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 62 ## DW_AT_encoding
+ .byte 11 ## DW_FORM_data1
+ .byte 11 ## DW_AT_byte_size
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 5 ## Abbreviation Code
+ .byte 52 ## DW_TAG_variable
+ .byte 0 ## DW_CHILDREN_no
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 2 ## DW_AT_location
+ .byte 24 ## DW_FORM_exprloc
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 6 ## Abbreviation Code
+ .byte 22 ## DW_TAG_typedef
+ .byte 0 ## DW_CHILDREN_no
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 7 ## Abbreviation Code
+ .byte 23 ## DW_TAG_union_type
+ .byte 1 ## DW_CHILDREN_yes
+ .byte 11 ## DW_AT_byte_size
+ .byte 11 ## DW_FORM_data1
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 8 ## Abbreviation Code
+ .byte 13 ## DW_TAG_member
+ .byte 0 ## DW_CHILDREN_no
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 56 ## DW_AT_data_member_location
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 9 ## Abbreviation Code
+ .byte 13 ## DW_TAG_member
+ .byte 0 ## DW_CHILDREN_no
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 56 ## DW_AT_data_member_location
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 10 ## Abbreviation Code
+ .byte 19 ## DW_TAG_structure_type
+ .byte 1 ## DW_CHILDREN_yes
+ .byte 11 ## DW_AT_byte_size
+ .byte 11 ## DW_FORM_data1
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 11 ## Abbreviation Code
+ .byte 13 ## DW_TAG_member
+ .byte 0 ## DW_CHILDREN_no
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 13 ## DW_AT_bit_size
+ .byte 11 ## DW_FORM_data1
+ .byte 107 ## DW_AT_data_bit_offset
+ .byte 11 ## DW_FORM_data1
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 12 ## Abbreviation Code
+ .byte 46 ## DW_TAG_subprogram
+ .byte 0 ## DW_CHILDREN_no
+ .byte 17 ## DW_AT_low_pc
+ .byte 1 ## DW_FORM_addr
+ .byte 18 ## DW_AT_high_pc
+ .byte 6 ## DW_FORM_data4
+ .byte 64 ## DW_AT_frame_base
+ .byte 24 ## DW_FORM_exprloc
+ .byte 122 ## DW_AT_call_all_calls
+ .byte 25 ## DW_FORM_flag_present
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 63 ## DW_AT_external
+ .byte 25 ## DW_FORM_flag_present
+ .ascii "\341\177" ## DW_AT_APPLE_optimized
+ .byte 25 ## DW_FORM_flag_present
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 13 ## Abbreviation Code
+ .byte 46 ## DW_TAG_subprogram
+ .byte 1 ## DW_CHILDREN_yes
+ .byte 17 ## DW_AT_low_pc
+ .byte 1 ## DW_FORM_addr
+ .byte 18 ## DW_AT_high_pc
+ .byte 6 ## DW_FORM_data4
+ .byte 64 ## DW_AT_frame_base
+ .byte 24 ## DW_FORM_exprloc
+ .byte 122 ## DW_AT_call_all_calls
+ .byte 25 ## DW_FORM_flag_present
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 63 ## DW_AT_external
+ .byte 25 ## DW_FORM_flag_present
+ .ascii "\341\177" ## DW_AT_APPLE_optimized
+ .byte 25 ## DW_FORM_flag_present
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 14 ## Abbreviation Code
+ .byte 52 ## DW_TAG_variable
+ .byte 0 ## DW_CHILDREN_no
+ .byte 28 ## DW_AT_const_value
+ .byte 15 ## DW_FORM_udata
+ .byte 3 ## DW_AT_name
+ .byte 14 ## DW_FORM_strp
+ .byte 58 ## DW_AT_decl_file
+ .byte 11 ## DW_FORM_data1
+ .byte 59 ## DW_AT_decl_line
+ .byte 11 ## DW_FORM_data1
+ .byte 73 ## DW_AT_type
+ .byte 19 ## DW_FORM_ref4
+ .byte 0 ## EOM(1)
+ .byte 0 ## EOM(2)
+ .byte 0 ## EOM(3)
+ .section __DWARF,__debug_info,regular,debug
+Lsection_info:
+Lcu_begin0:
+.set Lset0, Ldebug_info_end0-Ldebug_info_start0 ## Length of Unit
+ .long Lset0
+Ldebug_info_start0:
+ .short 4 ## DWARF version number
+.set Lset1, Lsection_abbrev-Lsection_abbrev ## Offset Into Abbrev. Section
+ .long Lset1
+ .byte 8 ## Address Size (in bytes)
+ .byte 1 ## Abbrev [1] 0xb:0x112 DW_TAG_compile_unit
+ .long 0 ## DW_AT_producer
+ .short 12 ## DW_AT_language
+ .long 47 ## DW_AT_name
+ .long 0 ## DW_AT_stmt_list
+ .long 71 ## DW_AT_comp_dir
+ ## DW_AT_GNU_pubnames
+ ## DW_AT_APPLE_optimized
+ .quad 0 ## DW_AT_low_pc
+ .long 0
+ .byte 2 ## Abbrev [2] 0x2a:0x10 DW_TAG_variable
+ .long 90 ## DW_AT_name
+ .long 91 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 16 ## DW_AT_decl_line
+ .ascii "\201\202\220\245\006" ## DW_AT_const_value
+ .byte 3 ## Abbrev [3] 0x3a:0x5 DW_TAG_const_type
+ .long 63 ## DW_AT_type
+ .byte 4 ## Abbrev [4] 0x3f:0x7 DW_TAG_base_type
+ .long 99 ## DW_AT_name
+ .byte 5 ## DW_AT_encoding
+ .byte 4 ## DW_AT_byte_size
+ .byte 5 ## Abbrev [5] 0x46:0x15 DW_TAG_variable
+ .long 103 ## DW_AT_name
+ .long 91 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 15 ## DW_AT_decl_line
+ .byte 9 ## DW_AT_location
+ .byte 3
+ .quad __type_anchor
+ .byte 6 ## Abbrev [6] 0x5b:0xb DW_TAG_typedef
+ .long 102 ## DW_AT_type
+ .long 116 ## DW_AT_name
+ .byte 1 ## DW_AT_decl_file
+ .byte 13 ## DW_AT_decl_line
+ .byte 7 ## Abbrev [7] 0x66:0x6c DW_TAG_union_type
+ .byte 4 ## DW_AT_byte_size
+ .byte 1 ## DW_AT_decl_file
+ .byte 1 ## DW_AT_decl_line
+ .byte 8 ## Abbrev [8] 0x6a:0xc DW_TAG_member
+ .long 118 ## DW_AT_name
+ .long 210 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 3 ## DW_AT_decl_line
+ .byte 0 ## DW_AT_data_member_location
+ .byte 9 ## Abbrev [9] 0x76:0x8 DW_TAG_member
+ .long 126 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 4 ## DW_AT_decl_line
+ .byte 0 ## DW_AT_data_member_location
+ .byte 10 ## Abbrev [10] 0x7e:0x53 DW_TAG_structure_type
+ .byte 4 ## DW_AT_byte_size
+ .byte 1 ## DW_AT_decl_file
+ .byte 4 ## DW_AT_decl_line
+ .byte 11 ## Abbrev [11] 0x82:0xd DW_TAG_member
+ .long 135 ## DW_AT_name
+ .long 210 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 6 ## DW_AT_decl_line
+ .byte 8 ## DW_AT_bit_size
+ .byte 0 ## DW_AT_data_bit_offset
+ .byte 11 ## Abbrev [11] 0x8f:0xd DW_TAG_member
+ .long 137 ## DW_AT_name
+ .long 210 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 7 ## DW_AT_decl_line
+ .byte 8 ## DW_AT_bit_size
+ .byte 8 ## DW_AT_data_bit_offset
+ .byte 11 ## Abbrev [11] 0x9c:0xd DW_TAG_member
+ .long 139 ## DW_AT_name
+ .long 210 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 8 ## DW_AT_decl_line
+ .byte 6 ## DW_AT_bit_size
+ .byte 16 ## DW_AT_data_bit_offset
+ .byte 11 ## Abbrev [11] 0xa9:0xd DW_TAG_member
+ .long 141 ## DW_AT_name
+ .long 210 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 9 ## DW_AT_decl_line
+ .byte 2 ## DW_AT_bit_size
+ .byte 22 ## DW_AT_data_bit_offset
+ .byte 11 ## Abbrev [11] 0xb6:0xd DW_TAG_member
+ .long 143 ## DW_AT_name
+ .long 210 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 10 ## DW_AT_decl_line
+ .byte 6 ## DW_AT_bit_size
+ .byte 24 ## DW_AT_data_bit_offset
+ .byte 11 ## Abbrev [11] 0xc3:0xd DW_TAG_member
+ .long 145 ## DW_AT_name
+ .long 210 ## DW_AT_type
+ .byte 1 ## DW_AT_decl_file
+ .byte 11 ## DW_AT_decl_line
+ .byte 2 ## DW_AT_bit_size
+ .byte 30 ## DW_AT_data_bit_offset
+ .byte 0 ## End Of Children Mark
+ .byte 0 ## End Of Children Mark
+ .byte 4 ## Abbrev [4] 0xd2:0x7 DW_TAG_base_type
+ .long 122 ## DW_AT_name
+ .byte 7 ## DW_AT_encoding
+ .byte 4 ## DW_AT_byte_size
+ .byte 14 ## Abbrev [14] 0x10b:0x10 DW_TAG_variable
+ .ascii "\201\202\220\245\006" ## DW_AT_const_value
+ .long 154 ## DW_AT_name
+ .byte 1 ## DW_AT_decl_file
+ .byte 21 ## DW_AT_decl_line
+ .long 91 ## DW_AT_type
+ .byte 0 ## End Of Children Mark
+ .byte 0 ## End Of Children Mark
+Ldebug_info_end0:
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